Indoor exercise is getting more and more popular during recent decades. One of the popular indoor exercise apparatuses is the stationary exercise bicycle. Currently, there are generally two categories of popular stationary exercise bicycles on the market, the upright and recumbent bicycles.
FIG. 1 shows a recumbent bicycle 10. The recumbent bicycle 10 comprises a seat back 11 and a seat 12 which has a geometry center 13A. The seat 12, usually mounted on a framework 16, is movable on a track 14 inclined at an angle of about seven degrees. The recumbent bicycle 10 has a pair of crank arms 18 and pedals 19. Both the crank arms 18 and pedals 19 are rotated about a crank axis. A handle 17 is attached to the recumbent bicycle 10 for grabbing while a user needs to push the pedals 19 in a condition of operating a high level resistance. Sometimes, the handle 17 may further comprise a heart rate grip for monitoring the heart rate condition of a user.
One drawback of the recumbent bicycle 10 is that a user's knee may interfere with the handle 17 when a user wants to comfortably lean on the seat back 11 and properly grab the handle 17 at the same time. If a user would like to avoid the problem of interference between the handle 17 and the user's knee, the user can move the seat 12 backward to a proper position which means the user can properly extend the legs during one portion of an exercise cycle. In other words, the user can properly extend the legs during a downward and backward cycle of the pedals 19. In the condition of properly extending the user's legs, the interference problem is avoided but another problem is created. The user can not grab the handle 17 properly as shown in FIG. 2. One way to solve the problem is that the user needs to bend forward at the waist in order to grab the handle 17. After a long operation of the recumbent bicycle 10, the back muscles of the user would suffer an uncomfortable stress because of the bending forward posture.
FIG. 3 shows a user moving the seat 12 forward in order to grab the handle 17 properly. In this condition, the user needs to give up the benefit of properly extending the legs. Another disadvantage of the recumbent bicycle 10 is that a vertical height 105 between the geometry center 13A and the crank axis is much less than the user's knee height. The user's knee and thigh may be elevated too much and the user's thigh may compress the user's abdomen, especially for some people who have an obesity problem.
FIG. 4 shows an upright bicycle 20. The upright bicycle 20 comprises a seat 22 which has a geometry center 23A. The seat 22, usually mounted on a framework 26, is movable on a seat support 24. The framework 26 is inclined at an angle of about seventy-three degrees. The upright bicycle 20 has a pair of crank arms 28 and pedals 29. Both the crank arms 28 and pedals 29 are rotated around a crank axis. A handle 27 is attached to the upright bicycle 20 for grabbing. In a general operating posture, a user needs to bend forward at the waist and the user's back and arms are burdened accordingly. For the foregoing reasons, there is a need for a stationary exercise bicycle to provide several ergonomic benefits which can make a user comfortably and easily operate the stationary exercise bicycle.